Within the petroleum industry, acids perform many functions, i.e. removing inorganic and organic scales, decarbonation, pH adjustment, general cleaning, and disinfecting; however, these acids can be highly dangerous to handle and transport, highly corrosive to metal surfaces, and can lead to the formation of mineral scales.
When crude oil production declines, there are a number of causes for the decline in production. Two reasons for a decline in oil production are (1) a reduction in the permeability of the oil “reservoir” or (2) the invasion of this reservoir by the water contained in a lower layer.
A reduction in permeability is typically due to the entrainment of fines, by the flow of the oil, towards the production well. Around this well, these particles accumulate and gradually plug the natural pores in the rock. The oil can then no longer flow out at an efficient rate through this well. These particles can be of various origins (e.g., type of rock, damage to the formation, progressive deterioration of the rock, etc.).
In order to remove these particles and improve the mobility of the oil in the formation, an acidic fluid can be injected into the well where some of the particles and some of the rock in the formation are partially soluble in this acidic fluid. Thus, this well stimulation method can cause these particles and rock to partially dissolve, and make the rock of the formation more porous thereby increasing the mobility of the oil in the formation and increasing well production.
A continuing need exists for alternative agents that are easier to handle, more environmentally benign, and have reduced corrosiveness.